1. Field of the Invention
The present invention relates electrical connectors and more particularly to a cable end connector, which comprises a tubular connection member, a core tube mounted in the tubular connection member, a plastic outer tubular member axially slidably coupled to the tubular connection member around the core tube, a retaining sleeve fastened to the around the core tube and an insulative holder block mounted in the core tube to hold a metal center pin and a metal clamp in the rear center hole of the metal center pin for quick installation of a coaxial cable without causing deformation of the center conductor of the coaxial cable or any damage to the aluminum foil shield of the coaxial cable.
2. Description of the Related Art
Following fast development of communication technology, signal transmission requires high stability and rapid speed. In consequence, different communication wire materials, from the early flat cable design to the modern round cable and optical cable designs, have been created to enhance signal transmission speed and capacity. Subject to the application of telephone technology, video technology and internet technology, global communication becomes faster and cheaper. Transmission of video signal through a cable assures signal stability and reliability. Therefore, closed-circuit TV is developed after the application of wireless TV and satellite TV. Establishing a closed-circuit television system requires installation of cables between the provider and the subscribers. When a cable is extended to the inside of a house, a cable end connector must be used to connect the cable to an indoor electric or electronic device. FIGS. 10 and 11 illustrate two similar cable end connectors according to the prior art. According to these two designs, the cable end connectors A commonly comprise a tubular connection member A1 having a connection portion A11 at the front side, an insulative holder block A12 mounted in the rear side of the tubular connection member A1, a metal center pin A13 fastened to the insulative holder block A12 and extending out of the connection portion A11 of the tubular connection member A1, an outer tubular member A2 connected to the rear side of the tubular connection member A1, a core tube A3 mounted in the outer tubular member A2 and stopped against the insulative holder block A12 and having an axial receiving chamber A30 defined therein, a barrel A4 sleeved onto the core tube A3, and a retaining sleeve A5 sleeved onto the barrel A4, and a plastic bushing A6 mounted in the retaining sleeve A5. After the cable end connector is assembled, the rear end edge A31 of the core tube A3 is kept spaced from the plastic bushing A6 and suspending in the retaining sleeve A5. When connecting the cable end connector to a coaxial cable B, the center conductor B1 of the coaxial cable B is inserted through the retaining sleeve A5, the plastic bushing A6 and the barrel A4 into the rear side of the metal center pin A13 and secured to a metal clamp A14 in the metal center pin A13, and then the retaining sleeve A5 and the plastic bushing A6 are pushed forwards to force the braided metal wrapper and outer plastic sheath of the coaxial cable B into the space in between the plastic bushing A6 and the core tube A3. In actual practice, these two prior art designs are still not satisfactory in function and have drawbacks as follows:    1. When connecting the cable end connector A and the coaxial cable B, it is necessary to insert the center conductor B1 of the coaxial cable B through the retaining sleeve A5, the plastic bushing A6 and the barrel A4 into the rear side of the metal center pin A13 to have the center conductor B1 be secured to the metal clamp A14 in the metal center pin A13. However, because the operator cannot see the position of the metal clamp A14 in the cable end connector when inserting the center conductor B1 of the coaxial cable B into the cable end connector, the center conductor B1 may be not accurately inserted into the rear side of the metal center pin A13, causing a contact error or signal transmission instability.    2. When connecting the cable end connector A and the coaxial cable B, the inner dielectric insulator B2 and aluminum foil shield B3 of the coaxial cable B are inserted through the retaining sleeve A5 and the plastic bushing A6 into the barrel A4 and then the receiving chamber A30 of the core tube A3. However, because the operator cannot visually check the alignment during insertion, the aluminum foil shield B3 of the coaxial cable B may be damaged accidentally, affecting signal transmission stability and reliability.
Therefore, it is desirable to provide a cable end connector, which facilitates quick and accurate connection of a coaxial cable without causing deformation of the center conductor of the coaxial cable or damage to the aluminum foil shield of the coaxial cable.